Elasticsearch is an open source project and we love to receive contributions from our community — you! There are many ways to contribute, from writing tutorials or blog posts, improving the documentation, submitting bug reports and feature requests or writing code which can be incorporated into Elasticsearch itself.
If you think you have found a bug in Elasticsearch, first make sure that you are testing against the latest version of Elasticsearch - your issue may already have been fixed. If not, search our issues list on GitHub in case a similar issue has already been opened.
It is very helpful if you can prepare a reproduction of the bug. In other words, provide a small test case which we can run to confirm your bug. It makes it easier to find the problem and to fix it. Test cases should be provided as curl commands which we can copy and paste into a terminal to run it locally, for example:
# delete the index
curl -XDELETE localhost:9200/test
# insert a document
curl -XPUT localhost:9200/test/test/1 -d '{
"title": "test document"
}'
# this should return XXXX but instead returns YYY
curl ....Provide as much information as you can. You may think that the problem lies with your query, when actually it depends on how your data is indexed. The easier it is for us to recreate your problem, the faster it is likely to be fixed.
If you find yourself wishing for a feature that doesn't exist in Elasticsearch, you are probably not alone. There are bound to be others out there with similar needs. Many of the features that Elasticsearch has today have been added because our users saw the need. Open an issue on our issues list on GitHub which describes the feature you would like to see, why you need it, and how it should work.
If you have a bugfix or new feature that you would like to contribute to Elasticsearch, please find or open an issue about it first. Talk about what you would like to do. It may be that somebody is already working on it, or that there are particular issues that you should know about before implementing the change.
We enjoy working with contributors to get their code accepted. There are many approaches to fixing a problem and it is important to find the best approach before writing too much code.
Note that it is unlikely the project will merge refactors for the sake of refactoring. These types of pull requests have a high cost to maintainers in reviewing and testing with little to no tangible benefit. This especially includes changes generated by tools. For example, converting all generic interface instances to use the diamond operator.
The process for contributing to any of the Elastic repositories is similar. Details for individual projects can be found below.
You will need to fork the main Elasticsearch code or documentation repository and clone it to your local machine. See github help page for help.
Further instructions for specific projects are given below.
Once your changes and tests are ready to submit for review:
-
Test your changes
Run the test suite to make sure that nothing is broken. See the TESTING file for help running tests.
-
Sign the Contributor License Agreement
Please make sure you have signed our Contributor License Agreement. We are not asking you to assign copyright to us, but to give us the right to distribute your code without restriction. We ask this of all contributors in order to assure our users of the origin and continuing existence of the code. You only need to sign the CLA once.
-
Rebase your changes
Update your local repository with the most recent code from the main Elasticsearch repository, and rebase your branch on top of the latest master branch. We prefer your initial changes to be squashed into a single commit. Later, if we ask you to make changes, add them as separate commits. This makes them easier to review. As a final step before merging we will either ask you to squash all commits yourself or we'll do it for you.
-
Submit a pull request
Push your local changes to your forked copy of the repository and submit a pull request. In the pull request, choose a title which sums up the changes that you have made, and in the body provide more details about what your changes do. Also mention the number of the issue where discussion has taken place, eg "Closes #123".
Then sit back and wait. There will probably be discussion about the pull request and, if any changes are needed, we would love to work with you to get your pull request merged into Elasticsearch.
Please adhere to the general guideline that you should never force push to a publicly shared branch. Once you have opened your pull request, you should consider your branch publicly shared. Instead of force pushing you can just add incremental commits; this is generally easier on your reviewers. If you need to pick up changes from master, you can merge master into your branch. A reviewer might ask you to rebase a long-running pull request in which case force pushing is okay for that request. Note that squashing at the end of the review process should also not be done, that can be done when the pull request is integrated via GitHub.
Repository: https://github.com/elastic/elasticsearch
JDK 10 is required to build Elasticsearch. You must have a JDK 10 installation
with the environment variable JAVA_HOME referencing the path to Java home for
your JDK 10 installation. By default, tests use the same runtime as JAVA_HOME.
However, since Elasticsearch, supports JDK 8 the build supports compiling with
JDK 10 and testing on a JDK 8 runtime; to do this, set RUNTIME_JAVA_HOME
pointing to the Java home of a JDK 8 installation. Note that this mechanism can
be used to test against other JDKs as well, this is not only limited to JDK 8.
Elasticsearch uses the Gradle wrapper for its build. You can execute Gradle
using the wrapper via the gradlew script in the root of the repository.
We support development in the Eclipse and IntelliJ IDEs. For Eclipse, the minimum version that we support is Eclipse Oxygen (version 4.7). For IntelliJ, the minimum version that we support is IntelliJ 2017.2.
Eclipse users can automatically configure their IDE: ./gradlew eclipse
then File: Import: Existing Projects into Workspace. Select the
option Search for nested projects. Additionally you will want to
ensure that Eclipse is using 2048m of heap by modifying eclipse.ini
accordingly to avoid GC overhead errors.
IntelliJ users can automatically configure their IDE: ./gradlew idea
then File->New Project From Existing Sources. Point to the root of
the source directory, select
Import project from external model->Gradle, enable
Use auto-import. In order to run tests directly from
IDEA 2017.2 and above, it is required to disable the IDEA run launcher in order to avoid
idea_rt.jar causing "jar hell". This can be achieved by adding the
-Didea.no.launcher=true JVM
option.
Alternatively, idea.no.launcher=true can be set in the
idea.properties
file which can be accessed under Help > Edit Custom Properties (this will require a
restart of IDEA). For IDEA 2017.3 and above, in addition to the JVM option, you will need to go to
Run->Edit Configurations->...->Defaults->JUnit and verify that the Shorten command line setting is set to
user-local default: none. You may also need to remove ant-javafx.jar from your
classpath if that is
reported as a source of jar hell.
To run an instance of elasticsearch from the source code run ./gradlew run
The Elasticsearch codebase makes heavy use of Java asserts and the
test runner requires that assertions be enabled within the JVM. This
can be accomplished by passing the flag -ea to the JVM on startup.
For IntelliJ, go to
Run->Edit Configurations...->Defaults->JUnit->VM options and input
-ea.
For Eclipse, go to Preferences->Java->Installed JREs and add -ea to
VM Arguments.
Please follow these formatting guidelines:
- Java indent is 4 spaces
- Line width is 140 characters
- The rest is left to Java coding standards
- Disable “auto-format on save” to prevent unnecessary format changes. This makes reviews much harder as it generates unnecessary formatting changes. If your IDE supports formatting only modified chunks that is fine to do.
- Wildcard imports (
import foo.bar.baz.*) are forbidden and will cause the build to fail. Please attempt to tame your IDE so it doesn't make them and please send a PR against this document with instructions for your IDE if it doesn't contain them. - Eclipse:
Preferences->Java->Code Style->Organize Imports. There are two boxes labeled "Number of (static )? imports needed for .*". Set their values to 99999 or some other absurdly high value. - IntelliJ:
Preferences/Settings->Editor->Code Style->Java->Imports. There are two configuration options:Class count to use import with '*'andNames count to use static import with '*'. Set their values to 99999 or some other absurdly high value. - Don't worry too much about import order. Try not to change it but don't worry about fighting your IDE to stop it from doing so.
We require license headers on all Java files. You will notice that all the Java files in
the top-level x-pack directory contain a separate license from the rest of the repository. This
directory contains commercial code that is associated with a separate license. It can be helpful
to have the IDE automatically insert the appropriate license header depending which part of the project
contributions are made to.
To have IntelliJ insert the correct license, it is necessary to create to copyright profiles.
These may potentially be called apache2 and commercial. These can be created in
Preferences/Settings->Editor->Copyright->Copyright Profiles. To associate these profiles to
their respective directories, two "Scopes" will need to be created. These can be created in
Preferences/Settings->Appearances & Behavior->Scopes. When creating scopes, be sure to choose
the shared scope type. Create a scope, apache2, with
the associated pattern of !file[group:x-pack]:*/. This pattern will exclude all the files contained in
the x-pack directory. The other scope, commercial, will have the inverse pattern of file[group:x-pack]:*/.
The two scopes, together, should account for all the files in the project. To associate the scopes
with their copyright-profiles, go into Preferences/Settings->Editor>Copyright and use the + to add
the associations apache2/apache2 and commercial/commercial.
Configuring these options in IntelliJ can be quite buggy, so do not be alarmed if you have to open/close the settings window and/or restart IntelliJ to see your changes take effect.
To create a distribution from the source, simply run:
cd elasticsearch/
./gradlew assembleThe package distributions (Debian and RPM) can be found under:
./distribution/packages/(deb|rpm)/build/distributions/
The archive distributions (tar and zip) can be found under:
./distribution/archives/(tar|zip)/build/distributions/
Before submitting your changes, run the test suite to make sure that nothing is broken, with:
./gradlew checkIf your changes affect only the documentation, run:
./gradlew -p docs checkFor more information about testing code examples in the documentation, see https://github.com/elastic/elasticsearch/blob/master/docs/README.asciidoc
This repository is split into many top level directories. The most important ones are:
Documentation for the project.
Builds our tar and zip archives and our rpm and deb packages.
Libraries used to build other parts of the project. These are meant to be internal rather than general purpose. We have no plans to semver their APIs or accept feature requests for them. We publish them to maven central because they are dependencies of our plugin test framework, high level rest client, and jdbc driver but they really aren't general purpose enough to belong in maven central. We're still working out what to do here.
Features that are shipped with Elasticsearch by default but are not built in to the server. We typically separate features from the server because they require permissions that we don't believe all of Elasticsearch should have or because they depend on libraries that we don't believe all of Elasticsearch should depend on.
For example, reindex requires the connect permission so it can perform
reindex-from-remote but we don't believe that the all of Elasticsearch should
have the "connect". For another example, Painless is implemented using antlr4
and asm and we don't believe that all of Elasticsearch should have access to
them.
Officially supported plugins to Elasticsearch. We decide that a feature should be a plugin rather than shipped as a module because we feel that it is only important to a subset of users, especially if it requires extra dependencies.
The canonical example of this is the ICU analysis plugin. It is important for folks who want the fairly language neutral ICU analyzer but the library to implement the analyzer is 11MB so we don't ship it with Elasticsearch by default.
Another example is the discovery-gce plugin. It is vital to folks running
in GCP but useless otherwise and it depends on a
dozen extra jars.
Honestly this is kind of in flux and we're not 100% sure where we'll end up. Right now the directory contains
- Tests that require multiple modules or plugins to work
- Tests that form a cluster made up of multiple versions of Elasticsearch like full cluster restart, rolling restarts, and mixed version tests
- Tests that test the Elasticsearch clients in "interesting" places like the
wildflyproject. - Tests that test Elasticsearch in funny configurations like with ingest disabled
- Tests that need to do strange things like install plugins that thrown
uncaught
Throwables or add a shutdown hook But we're not convinced that all of these things belong in the qa directory. We're fairly sure that tests that require multiple modules or plugins to work should just pick a "home" plugin. We're fairly sure that the multi-version tests do belong in qa. Beyond that, we're not sure. If you want to add a new qa project, open a PR and be ready to discuss options.
The server component of Elasticsearch that contains all of the modules and plugins. Right now things like the high level rest client depend on the server but we'd like to fix that in the future.
Our test framework and test fixtures. We use the test framework for testing the server, the plugins, and modules, and pretty much everything else. We publish the test framework so folks who develop Elasticsearch plugins can use it to test the plugins. The test fixtures are external processes that we start before running specific tests that rely on them.
For example, we have an hdfs test that uses mini-hdfs to test our repository-hdfs plugin.
Commercially licensed code that integrates with the rest of Elasticsearch. The
docs subdirectory functions just like the top level docs subdirectory and
the qa subdirectory functions just like the top level qa subdirectory. The
plugin subdirectory contains the x-pack module which runs inside the
Elasticsearch process. The transport-client subdirectory contains extensions
to Elasticsearch's standard transport client to work properly with x-pack.
In general Elasticsearch is happy to accept contributions that were created as part of a class but strongly advise against making the contribution as part of the class. So if you have code you wrote for a class feel free to submit it.
Please, please, please do not assign contributing to Elasticsearch as part of a class. If you really want to assign writing code for Elasticsearch as an assignment then the code contributions should be made to your private clone and opening PRs against the primary Elasticsearch clone must be optional, fully voluntary, not for a grade, and without any deadlines.
Because:
- While the code review process is likely very educational, it can take wildly varying amounts of time depending on who is available, where the change is, and how deep the change is. There is no way to predict how long it will take unless we rush.
- We do not rush reviews without a very, very good reason. Class deadlines aren't a good enough reason for us to rush reviews.
- We deeply discourage opening a PR you don't intend to work through the entire code review process because it wastes our time.
- We don't have the capacity to absorb an entire class full of new contributors, especially when they are unlikely to become long time contributors.
Finally, we require that you run ./gradlew check before submitting a
non-documentation contribution. This is mentioned above, but it is worth
repeating in this section because it has come up in this context.